QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: bubble on September 22, 2017, 10:24

Title: Why Ne=48?
Post by: bubble on September 22, 2017, 10:24

Hi,

https://docs.quantumwise.com/tutorials/parallelization/parallelization.html

Recently, I found in the above tutorial, in the 'unit-of-work' section, the tutorial indicates that the 'contour energy point' Ne is usually 48, and this confused me.

To my knowledge, the  contour intergral is divided into equilibrim and non-equilibrim parts. For the former the default value is 30, as indicated in the 'New calculator' panel. However, for the latter, only the default 'Real axis point density', 0.001Ha (about 0.0272eV), is given in the 'New calculator' . What I want to know is:

1. Is the energy point in the  non-equilibrim part equal to (about) 18 (i.e. 48-30=18)?
2. How to fix the number 18 or 48? To my knowledge, in the real axis the integral length should be dependent on the chemmical potential difference (i.e. uL-uR)? If so,  whether the energy point used in the real axis should be equal to (uL-uR)/0.001Ha, rather than 18?

Thank you!

Title: Re: Why Ne=48?
Post by: Ulrik G. Vej-Hansen on September 22, 2017, 10:34

48 is the default number of points for the default SemiCircleContour. There are three contributions, 30 for the circle, 10 on the line and 8 poles. See this link for more information: : https://docs.quantumwise.com/manuals/Types/SemiCircleContour/SemiCircleContour.html

Title: Re: Why Ne=48?
Post by: bubble on September 22, 2017, 10:42

Thank you for your reply!